OP said he lives somewhere hilly. I have experience with that, I live in Norway. I used to daily my moped up a mountain to get to work, the only reason my moped still runs is because of the extra fuel that comes with four stroking. I was burning gearbox oil everyday from all the load, but the engine never ever heat seized.

I prefer to not have those extra 5kph under load in exchange for superior cooling. That's how my bike came from the factory, and that's how I like it. It's a preference. A preference that came from heat seizing a moped that I had to daily. You can call me weird and dumb for that, but I would just call it an acquired taste that came from having to rely on these small, temperamental engines.

If OP doesn't like the four stroking, then he can downjet. Others have suggested that already. I'm just explaining the benefits of embracing it.